There is a slope where you can manual down to get plenty of manual experience easily. The slope is a road that, when you look down it, you should see a building with a "COME AGAIN!" sign on it. There is a spot challenge at the start of the slope. If you start it, you can manual all the way down. Don't worry about hitting all the spots or anything else. To earn easy experience, just go down the hill as far as possible. When you get to the bottom, instead of going up, just restart your last goal. You will be on the spot challenge again at the top of the hill. Repeat as desired.